Connective and supporting tissues
- are remarkable for well-developed intercellular substance with a heterogenous chemical composition and structure that depend on tissue type
- differ by the number of tissue-forming cell lineages (there can be one or more cell lineages)
- take part in maintaining homeostasis (steady internal environment) by exerting transport, trophic, protective, biomechanical (supporting), and plastic functions
- are derived from the mesenchyme
Intercellular substance (extracellular matrix) is produced by cells. It contains fibers and the ground (amorphous) substance
Fibers
Collagen fibers
- are formed by fibrous proteins, namely by collagen type I (loose and dense connective tissue, osseous tissue, dentine and cement of teeth) and type II (cartilage tissue)
- exhibit a higher strength and no potential to be stretched
- join into bundles, ensure the architecture and mechanical properties of connective tissues
Reticular fibers
- are formed by collagen type III (reticular tissue, loose connective tissue)
- are stained by silver salts, so these fibers are called argyrophilic
- construct 3D-networks and thus exert a sustentacular function
Elastic fibers
- are formed by such proteins as elastin and fibrillin
- are selectively stained by orcein and aldehyde-fuchsin
- branch and form anastomoses, ensure a potential for reversible deformation in connective tissue
Ground (amorphous) substance
- is constituted by macromolecular complexes of proteoglycans and glycoproteins
- can be hydrated or mineralized
- fills spaces between cells and fibers, participates in exerting the transport, trophic, and sustentacular function
Mesenchyme
- is formed during the embryogenesis by cell migration from the mesoderm (endomesenchyme) and neuroectoderm (ectomesenchyme)
- is a group of various cells (different in their determination) and jelly-like intercellular substance
- undergoes cell differentiation that depends on the surrounding cells